Method and Apparatus for High Temperature Heat Treatment of Combustible Material in Particular Waste

ABSTRACT

An apparatus ( 1 ) for high temperature heat treatment of combustible material comprising a pyrolysis chamber ( 41 ) and a combustion chamber ( 42 ). The full combustion of the combustible material produces gas at high temperature that is sent to the pyrolysis chamber in order to raise the temperature of pyrolysis. This associated to the introducing water vapour, through a duct ( 6 ), and of air, through a duct ( 7 ), in pyrolysis chamber ( 41 ) produce semiwater gas that is then burnt in combustion chamber ( 42 ) by feeding a current ( 8 ) of a fluid containing oxygen to raise the combustion temperature in order to carry out the process to temperature that assures the molecular break of the totality of the toxic substances.

PRIORITY CLAIM

This patent application is a U.S. National Phase of InternationalApplication No. PCT/EP2005/005996, filed Jun. 3, 2005, which claimspriority to European Patent Application No. 04425425.8, filed Jun. 10,2004, the disclosures of which are incorporated herein by reference intheir entirety.

FIELD OF THE INVENTION

The present invention relates to an apparatus for high temperature heattreatment of combustible material, in particular industrial andmunicipal waste of any kind, even toxic or noxious waste, for minimizingthe dangerousness of the combustion products. Furthermore, the inventionrelates to a pyrolytic converter for recovering the energy content ofthe waste.

BACKGROUND OF THE INVENTION

It is well known that systems traditionally used for waste disposal, inparticular municipal solid waste, provide either burying or burning thewaste. Either solution has problems of environmental impact. In case ofwaste burying, the risk is high of polluting for a very long time theunderlying ground water table owing to percolates; whereas, in case ofburning, even if macro-pollutants such as particulates and smoke can beretained, the amount of micro-pollutants introduced in the environmentis high.

In recent years attempts have been made for alternative systems. Inparticular, waste pyrolytic processes have been proposed, i.e., heattreatments for transformation of large molecules into simplersubstances. This transformation is made in an environment poor in oxygenand at a temperature high enough to volatilize the organic pollutants.More in detail, without oxygen, i.e., in a reducing environment,pyrolysis causes the thermochemical decomposition of the material. Theprocess, for its endothermic nature, causes the scission of the complexmolecules that form rubber, plastics, cellulosic components and othercomplex chemical components, turning them into structurally simplermolecules.

This way, at the end of the pyrolytic process, a gaseous combustiblemixture is obtained that can be used, for example, for feeding a gasturbine and producing electric energy. More in detail, the combustion ofthe waste causes a thermal decomposition and mineralisation of the manyorganic substances contained in the waste and a transformation ofinorganic substances into more easily separable species, which can berecovered or can be safely disposed of, thus allowing a huge reductionof the weight and of the volume of the waste (reaching up to 10% of thestarting volume).

The waste that can be treated in this type of plant may be residues frompaper, plastics, rubber converting processes, tires, as well ascombustible material obtained from biomass, such as wood and agricultureresidues, and even organic material such as waste of hospitals ortoxic/noxious industrial waste.

The substances emitted in the traditional combustion processes are thefollowing: dust, carbon monoxide, sulphur dioxide, nitrogen oxides,hydrochloric or hydrofluoric acid, heavy metals and chloride-organicsubstances (dioxins and furans).

In particular, the presence of dioxins and furans in the exhausted fluegas causes a strong environmental impact of the existing processes. Theproduction of dioxins and furans occurs mainly owing to a not fullcombustion of the waste products. For minimizing the creation of thesehighly polluting substances, the combustion process must provide: thesupply of a sufficient amount of oxygen, a high temperature and longtime of contact. Alternatively, the resulting dioxins and the furans canbe filtered with the aid of activated carbon (with very high costs ofoperation) or other filtering systems.

However, the existing apparatus for burning waste, for example of thetype described in U.S. Pat. No. 3,759,036 and U.S. Pat. No. 4,732,092,is not always capable of avoiding the emission of pollutants so that thepollutants fall within the limits provided by the environmental laws. Inother cases, instead, it is possible to fall within said limits onlywith the use of structurally complicated and expensive apparatus, inparticular concerning the energy necessary for completing the process.

SUMMARY OF THE INVENTION

A feature of the present invention provides a waste heat treatmentmethod that provides a strong reduction of the pollutants present in theflue gas with a considerable energy saving with respect to the solutionsof prior art.

Another feature of the present invention provides a waste heat treatmentmethod for conveying the gas products within a burning apparatus even inthe presence of very high temperature.

Another feature of the present invention provides such a waste heattreatment method that allows obtaining an optimal recovering of theenergy content of said waste.

Another feature of the present invention provides a pyrolytic converterthat carries out this method.

These and other features are accomplished with one exemplary method forhigh temperature heat treatment of combustible material, in particularof waste, the heat treatment being carried out between a pyrolysischamber, where the combustible material is heated in a reducingenvironment, and a combustion chamber, where the combustible material iscompletely burnt by introducing a current containing oxygen. The mainfeature of the method is that in the pyrolysis chamber gas at hightemperature and vapour are inserted, the introduction causing theproduction of semiwater gas. The gas at high temperature is burnt gasdrawn downstream of the combustion chamber. The semiwater gas formed inthe pyrolysis chamber, once reached the combustion chamber, is burntcausing a considerable rise of the combustion temperature. In otherwords, in the pyrolysis chamber the combustible material is heated in areducing environment up to a determined temperature suitable for causinga preliminary combustion, obtaining partially burnt material andsemiwater gas, comprising air gas and water gas. In the combustionchamber, located downstream of the pyrolysis chamber, the partiallyburnt material and the semiwater gas are then fed and subjected to afurther oxygenation/combustion with production of a gaseous mixture athigh temperature.

In particular, the production of semiwater gas in the pyrolysis chamberis carried out sending a vapour jet and a gas jet at high temperature onthe burning material which is arranged on a grid, and then the burningmaterial reaches the combustion chamber by moving the grid.Advantageously, the semiwater gas reaches a predetermined zone of thecombustion chamber according to a path different from that of thecombustible material.

In particular, the gas at high temperature produced in the combustionchamber can cross a post-combustion chamber within which a furtherheating is effected by feeding a further current containing oxygen withcompletion of the combustion. Then, the burnt gas produced in thepost-combustion chamber, having a low oxygen content, is sent to thepyrolysis chamber.

In a preferred embodiment of the method according to the invention, thegas produced in one of the chambers is transferred between a startingchamber and an arrival chamber by a system comprising a conveying fluidcurrent that is supplied within a duct that connects the chambers same.The said conveying fluid is fed into the duct direct towards the arrivalchamber at a suitable speed to cause a suction of the gas inside. Morein detail, both the high speed of the conveying fluid and its expansion,which occurs at the outlet arrival chamber, attract in the duct the samegas to convey, i.e., the semiwater gas or the burnt gas. The attraction,therefore, on one hand occurs by entrainment and on the other hand bypressure difference between the inlet and the outlet of the duct. Theabove can be exploited both for conveying the semiwater gas from thepyrolysis chamber to the combustion chamber, both for conveying to thepyrolysis chamber the gas at high temperature produced in the combustionchamber, or the burnt gas produced in the post-combustion chamber.

In particular, for conveying the gas at high temperature, or the burntgas, to the pyrolysis chamber, in the duct conveying water vapour is fedas conveying fluid. This way, the water vapour used as conveying fluidcan be also used to obtain water gas in the pyrolysis chamber.

The conveyance of the semiwater gas from the pyrolysis chamber to thecombustion chamber is made by sending in the duct variably oxygenatedconveying gas as conveying fluid. More in detail, according to theprocess conditions, it is possible to adjust the amount of oxygensupplied.

Advantageously, the burnt gas produced in the post-combustion chamberbefore being conveyed to the pyrolysis chamber is separated frompossible solid particles giving a vortical movement to the burnt gas,which separate from the solid particles by centrifugal acceleration.This can be made, for example, forcing the burnt gas against the wallsof said post-combustion chamber which are suitable for causing saidvortical movement.

Advantageously, a preliminary ignition step is provided suitable forheating the different chambers up to a determined temperature. Inparticular, the step of heating the pyrolysis chamber provides apreliminary ignition step for bringing the pyrolysis chamber up to adetermined temperature necessary so that the reactions take place forthe creation of air gas and of water gas. Then, the process is auto-fed.In fact, the production of the gaseous mixture comprising the air gasand the water gas is made sending an air jet and a vapour jet on theburning material in the pyrolysis chamber when the burning material hasachieved a measured temperature. When the air jet and the vapour jet aresent on the burning material the semiwater gas, i.e., air gas and watergas, is produced according to known reactions. More in detail, thereaction that causes the production of water gas is an endothermicreaction and the required energy is supplied by the reaction that causesthe production of the air gas that is instead an exothermic reaction.Sending then in the pyrolysis chamber a suitable amount of vapour and ofair, according to the parameters of the process used, in particularresponsive to the composition of the combustible material, in particularmunicipal solid waste, in steady conditions an auto-fed process isobtained.

Like for the pyrolysis chamber, also in the combustion chamber apreliminary heating step is provided suitable for bringing thecombustion chamber same to a determined temperature, in particular thisstep is made before conveying the burnt gas to the pyrolysis chamber.This to avoid conveying in the pyrolysis chamber gas with high contentof oxygen that would be potentially dangerous since the gas could giverise to explosions and backfire.

In particular, conveying in the pyrolysis chamber at least one part ofthe burnt gas produced in the post-combustion chamber is made only whenthe temperature in the different chambers has achieved determinedvalues. This because until the temperature in the combustion chamber hasnot achieved a determined value the amount of oxygen is very high andthen it is not possible sending the mixture of gas to the pyrolysischamber for not to affect its correct operation.

Advantageously, a step is provided of feeding the combustible materialin the pyrolysis chamber by forcing the combustible material through atapered duct in order to reduce its volume. This avoids dangerousbackfire, provides a semi-combustion of the combustible material andassists a measurement of its composition, in particular on the contentof carbon in order to adjust the flows and the temperature in thedifferent chambers of the apparatus.

Advantageously, downstream of the heat treatment of the combustiblematerial treatments are provided of reduction of the waste material. Inparticular, a treatment of neutralisation is provided, which exploitsthe produced heat during the heat treatment of the combustible materialmaking inert substances from the ashes deriving from the combustion.

More in detail, the ashes coming from the apparatus are superheated byjets of semiwater gas and by air at high temperature for then meltingand flowing through a crucible having an opening, an air or vapour jettransforming the ashes into inert grains. Or, the molten material can befed to special moulds, forming bricks for the building industry.

According to another exemplary embodiment of the invention, an apparatusfor heat treatment of combustible material, in particular waste,comprises a pyrolysis chamber where the combustible material is heatedin a reducing environment and a combustion chamber where the combustiblematerial is conveyed for being completely burnt, whose main feature isthat the pyrolysis chamber comprises means for feeding a gas at hightemperature drawn from the combustion chamber and vapour, in order tomake semiwater gas which, once reached the combustion chamber, is burntfor causing a considerable rise of the combustion temperature.

Means can be provided for conveying the semiwater gas from the pyrolysischamber to the combustion chamber according to a path different fromthat of the combustible material.

Advantageously, means are provided for connecting a starting chamber toan arrival chamber, in particular for conveying the semiwater gas fromthe pyrolysis chamber to the combustion chamber or for conveying atleast one part of the burnt gas up to the pyrolysis chamber, comprisingat least one duct communicating with both the chambers within which aconveying fluid current is fed, the said conveying fluid being suppliedto said duct at a suitable speed to cause a suction inside, inparticular of the semiwater gas or the burnt gas.

Advantageously, downstream of the combustion chamber a post-combustionchamber can be provided within which the gaseous mixture is furtherheated at high temperature obtaining burnt gas by feeding a currentcontaining oxygen, said further heating causing a full decomposition ofthe part of the gaseous mixture not yet dissociated.

Advantageously, means are provided for feeding the combustible materialin the pyrolysis chamber comprising means for forcing the passagethrough a tapered duct in order to reduce its volume.

According to an exemplary embodiment of the invention, the means forforcing the motion of the combustible material in the feeding ductcomprise a conical track system. In particular, the feeding means areassociated to means for measuring at least one parameter of process inthe pyrolysis chamber. This adjusts the feeding speed of the combustiblematerial in the pyrolysis chamber according to the variation of theparameters of process, in particular of the temperature in the pyrolysischamber.

Advantageously, in each chamber ignition means are provided suitable forgiving the starting energy necessary for activating the heat treatmentof the combustible material.

In particular, in the apparatus directional elements can be arranged ofrefractory material suitable for deflecting a flow of gas to determinedzones of the apparatus, said directional elements being arranged betweenthe different chambers of the apparatus.

Advantageously, in each chamber of the apparatus directional elementsare provided of the gas flow obtained during the heat treatment of thecombustible material. In particular, the directional elements of the gasflow are diaphragms suitably shaped of refractory material that definethe different chambers of the apparatus.

In each chamber of the apparatus, furthermore, ducts are provided forintroducing hot air.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and the advantages of the method and apparatus for hightemperature heat treatment of combustible material, in particular waste,according to the present invention will be made clearer with thefollowing description of an exemplary embodiment thereof exemplifyingbut not limitative, with reference to the attached drawings wherein:

FIG. 1 shows a schematic view of a first exemplary embodiment of anapparatus for high temperature heat treatment of combustible material,in particular waste, according to the present invention;

FIG. 2 shows a schematic view of an alternative exemplary embodiment ofthe present invention;

FIG. 3 shows a block diagram of the method for heat treatment of wasteoperated by the apparatus for FIGS. 1 and 2.

DESCRIPTION OF THE INVENTION

In FIG. 1, a first exemplary embodiment is diagrammatically shown of anapparatus 1, according to the present invention, for high temperatureheat treatment of combustible material, in particular municipal solidwaste (waste products), or combustible waste of a desired nature,provided that the combustible waste is a solid and not explosive waste.The apparatus comprises a pyrolysis chamber 41, where the material 85 totreat is heated in a reducing environment, up to a temperature suitablefor making a first molecular break of the substances present in thematerial, and a combustion chamber 42 within which a full combustion isachieved of the combustible material by introducing a predetermined flowof oxygen 8. The full combustion of the combustible material is carriedout only in combustion chamber 42 of the apparatus 1 and produces, inparticular, gas at high temperature that is directed back to pyrolysischamber 41 in order to remarkably raise the temperature of pyrolysis. Inaddition to this, water vapour 86, through a duct 6, and air 87, througha duct 7, are added into the pyrolysis chamber 41 to produce semiwatergas that is then burnt in combustion chamber 42 by feeding a current 8of a fluid containing oxygen to raise the combustion temperature inorder to carry out the process at a temperature that assures themolecular break of the totality of the toxic substances. According tothe invention, a part of the burnt gas 88 produced by the combustion ofthe burning material 85 in combustion chamber 42 is sent to pyrolysischamber 41 through a duct 80 by introducing a conveying fluid 81. Thecurrent of burnt gas 82 that reaches pyrolysis chamber 41 crosses theburning material to cause the production of the semiwater gas.

In FIG. 2 an alternative exemplary embodiment is diagrammatically shownof the apparatus 1 of FIG. 1. The substantial difference with theprevious exemplary embodiment is the presence of a post-combustionchamber 43 downstream of combustion chamber 42. In both cases, apreliminary step is always provided of feeding the waste subject to heattreatment in pyrolysis chamber 41 through a tapered duct 20, block 101of FIG. 3. In duct 20, the waste is preheated up to a temperature ofabout 300° C. exploiting the heat produced in pyrolysis chamber 41, andthat may be assisted with the use of a electrical resistance, not shownin the figure, arranged along the duct same. The feeding of the wastethrough duct 20 is effected by a system of toothed tracks 55 that at thesame time compress and push forward the waste that in pyrolysis chamber41 roll on a first hot deflector 61 and then fall on a movable grid 50arranged inclined in pyrolysis chamber 41.

The feeding system above described causes a considerable reduction ofthe volume of the waste and reduces the possibility of backfire frompyrolysis chamber 41, making also easier both the steps ofsemi-combustion of the waste same and a satisfactory measure of thecontent of carbon in the introduced waste. The content of carbon in theintroduced waste is strictly linked to the nature of the waste treatedand is a parameter of process of primary importance, on the basis ofwhich the gas flows introduced in the apparatus are then adjusted.

In pyrolysis chamber 41 and behind combustion chamber 42 ignition meansare arranged, for example, methane gas burners 25, for bringing thetemperature in the chamber to a determined temperature beyond which thesystem practically is auto-fed and does not require other supply ofenergy from the outside. Once achieved the determined temperature, infact, the burner 25 can be deactivated, since the material present inthe pyrolysis chamber continues burning for the heat transmitted forconductivity from the combustion chamber. In steady conditions thetemperature in the pyrolysis chamber is about 800-900° C. and allows togasify a large part of the material deposited on grid 50, block 102 ofFIG. 2.

Once achieved a determined temperature in pyrolysis chamber 41 ancompressed air jet 11 and a water vapour jet are directed onto thematerial at high temperature to create a semiwater gas comprising watergas and air gas, as previously said, according to known reactions. Inparticular, the reaction that causes the production of the air gas is anexothermic reaction, i.e., the reaction occurs with release of a certainamount of energy, which is used for the reaction that produces watergas, which is instead an endothermic reaction, i.e., the reaction occurswith absorption of energy. On this basis, the system can be said to becompletely auto-fed.

The semiwater gas produced as above has a heating power that, even ifnot comparable to that of traditional fuel, is in any case high enoughbecause when burning the semiwater gas an amount can be obtained ofenergy to cause a further remarkable rise of the temperature. In orderto exploit the potentiality of the semiwater gas versus energy, the gasis in part transferred from pyrolysis chamber 41, where the gas has beenjust produced, to combustion chamber 42. The semiwater gas can beconveyed, for example, through a duct 21 in which a conveying fluidpasses and connecting pyrolysis chamber 41 with combustion chamber 42.More in detail, into duct 21 a conveying fluid current is fed at asuitable speed to cause a suction of the semiwater gas inside, alsoowing to the expansion of the conveying fluid same that occurs when theconveying fluid reaches combustion chamber 42. In particular, in duct 21two channels are arranged, a first channel fed with air with a variableoxygen content according to the process needs, and the second channelfed with a current of vapour. This exemplary embodiment avoids the useof fans or other propelling systems to convey the semiwater gas, with aconsiderable energy saving and reduction of maintenance costs. Thevapour is superheated in a way not shown using the heat of the burntgas.

From the pyrolysis chamber, the partially burnt material present on grid50 burns in low oxygenated conditions and forms a “brazier” that isrepeatedly transferred to combustion chamber 42, block 103. This is madeby grid 50 that is moved in the direction indicated by the arrows in thefigure. At the two sides of the waste feeding tapered duct, two ductsare provided that end in combustion chamber 42 with two spray nozzleseach, one for compressed air and one for oxygen, oriented towards therear part that carry the gas formed in the high part of pyrolysischamber 41. In pyrolysis chamber 41 sensors can be arranged formeasuring parameters of process such as temperature, pressure and carboncontent or the amount of unburnt hydrocarbons on the basis of which theinlet flows are adjusted.

In the combustion chamber 42 an almost complete combustion of thecombustible material is achieved, in part entrained by the gas flow andin part displaced by grid 50. The combustible material under heattreatment is hit by jets of extremely hot air, which burning completesthe combustion of the waste that was already carbonized in pyrolysischamber 41.

The gas produced by the combustion of the material arranged on grid 50in combustion chamber 42 moves upwards and in the higher part of chamber42 mixes with the air and the semiwater gas flowing from pyrolysischamber 41 and that are burning at high temperature (1200-1400° C.).

In combustion chamber 42 a further air flow is supplied at hightemperature through a duct 11. The warm air exits at a diaphragm 62 thatdivides combustion chamber 42 from a third chamber, or post-combustionchamber 43, crossing combustion chamber 42 in the centre and oxygenatingthe remaining partially burnt waste in addition to lateral semiwater gasflows. This way, the temperature is further raised up to about 1600° C.that provides a substantially total dissociation of the moleculespresent.

The burnt gas comes then to a third chamber, or post-combustion chamber,in which the burnt gas is further oxygenated by extremely hot air comingfrom a duct 12. In the last part of this post-combustion chamber,immediately behind another flow-deflecting diaphragm 63, which, as inthe other two diaphragms, is made of special refractory material, beforethat the “flue gas” reaches a vapour generating heat exchanger, twoopposite and oblique vapour jets slightly cool the gas and create avertical current for causing the loss of solid particles and forincreasing the heat exchange coefficient within the heat exchanger. Inthis zone of the plant a part of burnt gas is drawn back for beingconveyed to the pyrolysis chamber by means of water vapour. This can bemade, for example, by a duct 80 in which the vapour is inserted at highpressure and at a high speed through an inlet 81. The high speed of thevapour and the expansion that is achieved at the outlet 83 when enteringpyrolysis chamber 41 attracts the burnt gas produced in thepost-combustion chamber 43 into duct 80 causing conveyance of the burntgas through the duct, using the same system as above described forconveying the semiwater gas from pyrolysis chamber 41 to combustionchamber 42.

The apparatus 1 for heat treatment of waste can be coupled to systems ofreduction of polluting residues. In particular, the burnt gas comingfrom the post-combustion chamber 43 still hot and containing residueparticles, can be “washed” and cooled further in a scrubber, block 107.In the first part of the scrubber, any solid or gaseous substances whichescaped from dissociation in post-burner 43 are precipitated andcaptured. In the second part of the scrubber, the same reactions arerepeated as in the first part, but with the addition of water and basicreactants, in order to eliminate any residue acid substances. In thescrubber sludge is formed that is then put in the heat treatment cyclefor being inertized.

Finally, the gas can be conveyed through a biofilter before beingreleased in the atmosphere, in order to provide complete removal oftoxic and noxious substances. The action of the biofilter begins with asaturation of the gas, by water vapour, to pass then to the first layer,comprising lignite and organic carbon, in which colonies of speciallyselected bacteria live. From here the gas passes through a second layer,comprising peat, also this containing colonies of specially selectedbacteria, different from the previous and that selectively attack otherproducts; in a third and last layer, formed by chips and saw dust ofwood, other bacteria are present that together with a catalyst attackany residue possible molecules of furans or dioxins.

Similarly, a system of reduction of any solid residues produced by theapparatus 1 is provided, i.e. the ashes, blocks 104 and 106. The hightemperature reached in the apparatus 1, allows melting the ashes thatare gathered in reservoir 71 located at combustion chamber 42. The ashesalready at high temperature, are superheated by jets of water gas and ofvery hot air, and are conveyed in a crucible with a hole in the centre,from which the molten material flows and falls, entrained by a jet ofcompressed air or vapour, into cold water, creating inert pellets.Alternatively, the molten material is supplied into moulds formingbricks, for example, self-locking for pavements or garden pathways. Thehardness of the bricks can be adjusted with the addition to the ashes ofsilica and soda.

The foregoing description of a exemplary embodiment will so fully revealthe invention according to the conceptual point of view, so that others,by applying current knowledge, will be able to modify and/or adapt forvarious applications such an embodiment without further research andwithout parting from the invention; and it is therefore to be understoodthat such adaptations and modifications will have to be considered asequivalent to the exemplary embodiment. The means and the materials torealise the different functions described herein could have a differentnature without, for this reason, departing from the field of theinvention. It is to be understood that the phraseology or terminologyemployed herein is for the purpose of description and not of limitation.

All patents, applications, and publications referred to herein areincorporated by reference in their entirety.

1. A method for high temperature heat treatment of combustible material,comprising: a) heating said combustible material in a reducedenvironment in a pyrolysis chamber, wherein gas and vapour areintroduced at high temperature into the pyrolysis chamber, saidintroduction causing the production of semiwater gas; and b) completelyburning said combustible material in a combustion chamber; wherein thegas at high temperature is burnt gas drawn downstream from thecombustion chamber, said semiwater gas formed in the pyrolysis chamberis burnt once the gas reaches the combustion chamber, whichsubstantially increases the combustion temperature.
 2. The method ofclaim 1, wherein the semiwater gas is produced in the pyrolysis chamberso as to direct a vapour jet and a gas jet at high temperature onto theburning material which is arranged on a grid, and then the burningmaterial is urged to said combustion chamber by moving along the grid.3. The method of claim 1, wherein the semiwater gas reaches apredetermined zone of the combustion chamber according to a pathdifferent from that of the combustible material.
 4. The method of claim1, wherein the gas at high temperature produced in the combustionchamber crosses a post-combustion chamber within which a further heatingis effected by feeding a current containing oxygen with completion ofthe combustion, the burnt gas produced in the post-combustion chamberhaving a low oxygen content and is in part sent to the pyrolysischamber.
 5. The method of claim 1, wherein a gas produced in thepyrolysis chamber or the combustion chamber is conveyed between astarting chamber and an arrival chamber by a system comprising aconveying fluid current that is supplied within a duct that connects thechambers, said conveying fluid is supplied to the duct directed towardssaid arrival chamber at a speed sufficient to cause a suction of the gasinside the duct.
 6. The method of claim 5, wherein conveying said burntgas to the pyrolysis chamber is made sending in the duct water vapour asconveying fluid, said water vapour is used to obtain water gas in thepyrolysis chamber.
 7. The method of claim 6, wherein conveying saidsemiwater gas from the pyrolysis chamber to the combustion chamber ismade sending in the duct variably oxygenated gas as conveying fluid, theamount of oxygen supplied being adjustable according to the processconditions.
 8. The method of claim 1, wherein said burnt gas beforeconveyance to the pyrolysis chamber is separated from possible solidparticles by suspension giving a vortical movement of the burnt gasseparated from the solid particles by centrifugal acceleration.
 9. Themethod of claim 1, further comprising feeding the combustible materialin the pyrolysis chamber that is made forcing the passage through atapered duct in order to reduce the volume of the combustible material.10. An apparatus for heat treatment of combustible material, comprising:a) a pyrolysis chamber for containing combustible material heated in areducing environment; and b) a combustion chamber to which saidcombustible material moves for being completely burnt; wherein thepyrolysis chamber comprises means for feeding a gas at high temperaturedrawn from the combustion chamber and vapour, in order to make semiwatergas which, once reached said combustion chamber, is burnt so as tosubstantially increase the combustion temperature.
 11. The apparatus ofclaim 10, further comprising means for conveying the semiwater gas fromthe pyrolysis chamber to the combustion chamber according to a pathdifferent from that of the combustible material.
 12. The apparatus ofclaim 10, further comprising a post-combustion chamber disposeddownstream from the combustion chamber within which a further gas isfurther heated at high temperature obtaining burnt gas by feeding acurrent containing oxygen, the further heating causing a fulldecomposition of the part of the gas not yet dissociated.
 13. Theapparatus of claim 10, further comprising means for connecting astarting chamber to an arrival chamber, in particular for conveyingsemiwater gas from the pyrolysis chamber to the combustion chamber orfor conveying at least one part of said burnt gas up to the pyrolysischamber, said means for connecting comprising at least one ductcommunicating with both chambers among which the conveyance has to beexecuted, within which a conveying fluid current is fed, said conveyingfluid being supplied to the duct at a suitable speed to cause a suctioninside, in particular of the semiwater gas or of the burnt gas.
 14. Theapparatus of claim 10, further comprising means for feeding saidcombustible material in the pyrolysis chamber comprising means forforcing the passage through a tapered duct in order to reduce the volumeof the combustible material.
 15. The apparatus of claim 10, wherein thegas flow obtained during the heat treatment of the combustible materialis provided to each chamber of the apparatus directional elements.